AN ECOLOGICAL BACKGOUND

TO CONCEPTS OF LAND HUSBANDRY

(Extracted from Downes, 1982)

INTRODUCTION

"Unless there is a positive commitment by the Government and people ... for looking after their resources for future generations as well as the present, then conservation concepts become meaningless.

"The most important requirement at present is for everybody to be made to understand that soil conservation is more than erosion control and that it is not just an agricultural problem. Soil conservation is really a matter of applying the appropriate uses to different kinds of land.

TECHNICAL CONSIDERATIONS FOR GOOD LAND USE

"Conservation is a man-made concept concerned with how man relates to his land and uses its resources. The objective is to determine and put into practice how he can satisfy his physical and aesthetic needs from the land without spoiling its capability for continuing to satisfy those needs.

"To be successful, man must understand the ecological dynamics of different kinds of land and use that knowledge to devise non-destructive systems of land use and management for each kind of land. The knowledge of how land will react to imposed changes is the basis for making decisions about land use and management so as to maintain the capability for the chosen use.

"Land is the basic resource of a nation. To provide for all of his needs, man must use land for many purposes. He needs land to produce food, fibre, timber and water, for urban and industrial purposes, for transport by roads, railways and airports, for the extraction of minerals and building materials, for distributing power by transmission lines and pipelines and for the safe disposal of wastes. But he also needs land for non-productive purposes: for recreation and enjoyment; and land in its natural state to serve as reference areas and as habitat for the vast array of species of plants and animals, a great repository of genetic material that could be of value in the future.

"Apart from those uses needed for subsistence, all other uses are of equal necessity although the priorities of different communities for uses of land may change from time to time.

"Some uses of land such as agriculture are flexible because that use does not preclude many other future uses and it is easy to change to the other use. Some uses such as urban and industrial uses and forest plantations are inflexible because once the use is imposed it must continue for a long time. A use such as open space for recreation does not affect the capability for other uses, but ones like open cut mining change the nature of the land and preclude most options for future use.

"Uses such as scientific reserves and water catchments are compatible with each other and the land can be used for both purposes at the same time by multiple use; other uses such as agriculture and scientific reserve are incompatible and a choice must be made.

"Land varies from place to place in the landscape. Different land has different characteristics and different capabilities. The character of the land in any place is determined by the particular combination of the features of which it is composed: the topography, soil, hydrology, fauna and flora and the climate in which it is located.

"The nature of the features and the character of the land is the result of a long evolutionary period of interaction between the features in the prevailing climate. Where the interactions have been the same in the landscape, the same kind of land is to be found. Consequently the variations of land and the spatial arrangement of different kinds of land in the landscape are not due to chance but to different types of interactions. These differences can be studied and explained and used to determine the nature of the land, its capability for various kinds of use, the hazard of using it for different purposes and the relationship and interaction between the land occupying different situations in the landscape.

"In the natural state, land has a dynamic equilibrium. Although it may appear to be unchanging, the interactions are continuing. Within each kind of land there is a community of plants and animals which, from among the species available, are appropriate populations of those best able to live in association and competition with each other under the prevailaing climatic, topographic, hydrologic and soil conditions. The trend of the interactions and the resulting succession of different species of plants and animals is towards a maximum sustainable biological productivity attainable from the available array of species.

"When man uses land for plant and animal production he changes the natural systems because the existing maximum sustainable biological productivity is either not sufficient or not what he wants. Some kinds of land can be changed without becoming unstable, but others in which the stability depends on specially adapted plants, or a particular hydrologic balance or some other special feature can easily become unstable. Unless the imposed system of use and management incorporates precautions for maintaining a new stability, land degradation occurs. Man has failed to understand that ecological principles must be applied to devise suitable stable systems of use and management for different kinds of land. Clearing land of its original vegetation, cultivating, burning and introducing new species of plants and animals are significant changes that can equal in their effect the rare catastrophic changes during geological time that set off sequences of erosion and reshaping of the topography. The altered hydrology and the long periods when bare soil is exposed to the effects of sun, wind and rain are the basic causes of land degradation.

"But land degradation is not always due to changes made for agriculture. Badly located urban development, badly sited roads, bad forest harvesting and a whole range of man's activity can cause instability and degradation.

"Some people have sought a solution by trying to correct land degradation after it has occurred. This is a negative approach which implies that whenever land is used, degradation is an inevitable consequence which can only be controlled. The ecological approach to land use and soil conservation is much more positive. It is based on understanding the land, its capability for use and the hazards that must be overcome when used for different purposes. The objective is to use land only for purposes within its capability by perceiving the potential causes of instability and designing the system of use and management to overcome them.

"Achieving soil conservation will require good decisions by many people and not only those who are using the land. For this reason ecological principles can be used to provide guidelines for decision making if land degradation is to be avoided.

- Decisions should be made on the basis of adequate information about the land, its character, its capability for different uses, the hazards to be overcome when used for different purposes and its relative suitability for the various available options for use.

- Decisions should be made on the basis that different kinds of land have different potentialities for various uses, the most valuable land being that eminently suitable for a number of uses.

- Land having the potential for many uses should, as far as possible, be maintained under a flexible form of use to retain the greatest possible range of options for the future.

- Multiple use of land should be used to the greatest possible extent.

- Development of new land for production should be in response to real social or physical need; undeveloped land is the most flexible form of land use; it retains the widest possible range of options to cater for future needs.

- Decisions to use land for particular purposes should take into account not only the likely hazard of degration to that land but also to other land.

- Before deciding about using land for a particular purpose suitable management to prevent hazards must be available.

"The real problem is inappropriate systems of land use. When land is cultivated too much and develops a compaction layer, and it is left without vegetative cover for far too long in each year and the rotations have no provision for a restoration phase that will improve the structure, organic matter and fertility, the land is vulnerable.

"The soil loses its structure, the infiltration capacity is reduced, the chances of increased water flow across bare soil is increased and soil erosion occurs more frequently.

"The emphasis on erosion and its control, the erodibility of soils and permissible amounts of soil loss is a negative and unsatisfactory attitude.

"... those using the land, making decisions about its use or conducting research must develop a new attitude based on ecological principles. They must understand that any act of manipulating land produces reactions. These reactions must be perceived and taken into account in managing and using the land if land degradation is to be prevented.

"In future, land must be looked on as a resource to be nurtured and used appropriately and not as a commodity to be traded or as a raw material to be wasted by inappropriate use.

A PHILOSOPHY ABOUT LAND AND ITS USE

"A better community attitude to land can only come from the development of a philosophy about the land and its significance

to the welfare of a community. Such a philosophy will engender a widespread attitude that conforms with it.

"At present people in many countries have no clear understanding about the nature of land, land use, soil conservation or even about man's relation to the environment and his dependence on the land and its productivity.

"While this confusion exists it is difficult for any stated policy and objectives about land to emerge. The acceptance of a philosophy based on ecological principles will be technically correct and will provide the basis for suitable policy and objectives for attaining good land use and preventing land degradation.

"Acceptance of the following statements would serve as a suitable philosophy:

- The land is the basic resource of a nation and its use and management in a manner that causes degradation or destruction is undesirable because it affects the welfare of the whole community.

- Different kinds of land are dynamically balanced ecological systems which will be degraded or destroyed if the system of use and management imposed on them does not provide stability also.

- The kind and degree of manipulation that can be imposed safely on any land system to provide for the wide variety of needs of the community depends on the ecological characteristics of the system.

- The use of land should be based on an understanding of its ecological characteristics, the limitations of its capability and the need to obviate the hazards that would cause degradation if submitted to some kinds of land use and management.

- The requirements of the community can be satisfied only by submitting land to a variety of uses required to satisfy the different needs. Decisions about the future development use and management of the land and its resources should be made in an integrated and comprehensive way taking into account the total needs of the community now and in the future, and making use of the land and its associated water systems to the greatest possible extent for the uses for which they are most suitable.

- Land having the potential for a wide range of uses should be maintained in flexible forms of use as far as possible.

- In using land and its resources long term advantage should be pursued, rather than short term expediency that will lead to exploitation, degradation and finally destruction."

REFERENCE

DOWNES R G, 1982. 'Institution Building for Soil and Water Conservation in Brazil'. Consultant's report to Project BRA/82/011. Rome: FAO (AGLS). pp.43. (unpubd.)